Precision boring machine



c. PLEGER 2,086,284

PRECISION BORING MACHfNE July 6, 1937.

Filed Oct. 31, 1935 2 Sheets-Sheet l- 6. P/eg i" July 6, 1937.

c. PLEGER PRECISION BORING MACHINE Filed Oct. 31, i955 2 Sheets-Sheet 2 Wen/Z01; 611 16312).

. hitherto been-attained in spite of great weight curacy. I 55 Patented July 6, 1937 f 2 234 I I UNITED STATES PATENT OFFICE PRECISION BORING MACHINE Curt Pleger, Vienna, Austria, assignor to Ernst Krause & Co. A. 6., Vienna, Austria Application October 31,1935, Serial No. 47,699 In Germany November 5, 1934 2 Claims. (Cl. 77. 4)

Precision boring machines having horizontal which is attended by difliculties with regard to working spindles have been proposed in which their accommodation and in spite of a limited the driving means for the spindles and the driving reach. I means of themachine are housed in a box-form The present invention has for its object to pro- 5 bed. These machines have the drawback that vide a precision boring machine having one or 5 the rotating parts are arranged high above the more spindles which is intended moreparticulab floor, so that owing to this and to the power 1y for producing accurate bored holes, such as for drive considerable vibrations and shocks are set example are required in the case of internal comup in the box-'form bed. A further drawback bustion engines or the like. Such a machine can consists in this that there is doublebearing play be employed for all purposes in which precision 10 (in the spindles and in the slide). bored holes have to be produced. The new ma- In the case of horizontal precision boring machine has the advantage over the hitherto prochines having one or moreispindles, in which the posed machines that its weight for a similar powspindles are journ'alled in a bearing in such a er is much lower. The machine according to manner as to be immovable in the axial direction the invention consists in the combination of 15 and the work is mounted upon a displaceable known features and is characterized substantially slide, there is double bearing play, namely in the by this, that the boring spindles are arranged spindle hearings .on one hand and in the slide without the power driving means in a box-form track on the other hand, whereby the accuracy bed on the upper face of which the work is held of the work sufiers. down, the spindles operating upwardly from be- 20} In vertical standard boring machines in which low and the same bearing means serving for the spindle is journalled in a bearing which is disguiding the spindles during their rotary and axial placed on a slide or in a sleeve, or in which the feed motions. Upo t upper face of the bearing is axially immovable and a heavy table, shaped bed is provided a slide upon which the 1 which can only be prevented from canting with' work is to be clampe l 25 i1 difliculty, is raised and lowered, thereis the same The combination according to the invention has drawback. Moreover, in this case the accommothe following advantagesz-all the driving parts dation conveniently of work of considerable size of the machine are housed within the box-form .is prevented owing to the fact that the work has bed in proximity to the ground, while the driving first of all to-be bedded down upon a table which motor is arranged behind the machine so that 30 has been moved out laterally and has subsequentvibrations due to the motor are completely avoidly to be brought under the spindle centre. vFured and all vibrations due to non-synchronous ther thesemachines have a limited reach between running of a plurality of spindles with respect to the boring spindles and the wall of the machine one another are eliminated.

standard, so that work having large projections" Owing to the convenient supervision height 35 or the like cannot be operated upon at all or can of the machine the work tcbe operated on can only be operated upon with difliculty. If these be readily clamped down in position as desired. machines are constructed withaplurality of spin- The work table lies entirely free so that even dies then vibrations are set up which are due bulky work can be operated upon, which in-the 40 mainly to the spindles not running synchronouscase of column precision boring machines having 40 ly and suchvibrations can only be taken up with of course a limited reach is not possiblel dimculty even by standards of considerable Each of the boring spindles which operates strength. upwardly from below is guided in a bearing Some of the drawbacks of these precision borwhich not only allows the spindleto rotate thereing machines are avoided in the known single in but also serves for guiding the spindle during 45 spindle fine boring machines, which are conits feed motion, the said bearing being solidly structed as a rule as pedestal machines. In theanchored in the rigid box-form body. 1 case of some of the known pedestal precision bor- The construction in accordance with the ining machines, the safne bearing means serve for vention enables a machine to be provided of guiding the spindle during its rotary and feed light w t, which s v stable and quite e 50 motions so that there is only one bearing plane from vibration. This type of construction em and the accuracy of the work is considerably inables from 1 to 8 spindles'to be employed without creased. Freedom from vibration, however, above trouble, the distance apart of these spindles beingv all in the case of multi-spindle machines, has not capable of being readily adjusted with great ac- The new machine is illustrated in one constructional example in the accompanying drawings, in which Fig. 1 is an elevation of the machine.

Fig. 2 is a section through the upper part of a spindle with its bearings.

Fig. 3 a section on X-X of Fig. 2.

Fig. 4 shows the indicating device for locating the work-table in section.

Fig. 5 shows the same in horizontal section.

Fig. 6 is a side elevation of the machine with driving unit.

Referring to the drawings, l is the box-shaped bed or base on which is mounted thelower part 2 of the table, which is fixed to the bed, and 3 is the slide on which the plate 4 for fixing the work is rigidly mounted. On the fixing plate 4 rests is disposed the drive for the spindles l which the work to be operated on, for instance, two

four-cylinder blocks 5 for motor car engines. The

two work pieces 5 are held lightly and centered on the fixing plate 4 by means of the fixing device 6. In the bed I, near the base of the same receive" their rotary motion from belt pulleys lying in one plane. Through the control casing 8 disposed laterally on the bed the quick-motion feed and the workingfeed of the spindles I in both directions is produced. The whole machine receives its drive from a driving unit positioned behind the machine, for. instance an electric motor. The motor drives a gear box 30 in which the different spindle speeds are obtained by changing toothed wheels. This box also contains the clutch and brake for starting and stopping the spindles. The gear box drives a longitudinal shaft 3| in the bed I, which in'turn drives'the separate spindles.

The feed box 32 receives the quick-motion feed from the steadily running shaft of the gear box 30, and the working feed from the shaft 3|. The different feed motions are obtained by inserting change wheels. The clutches for the quickmotion and working ieed are actuated by a control disc'in the box 8, a semi-automatic operation of the machine being obtained bymeans of adjustable 'cams. The working feed is transmitted by'a noiseless chain from the feed box to an articulated shaft 33 which drives the threaded,- feed spindle of the separate spindle brackets by means of a worm and worm wheel. The electric motor is put into and out of operation by the pedal 9. By moving the main lever I!) to the right thespindles l are put in rotation and the quick-motion feed is put in operation, which brings the spindles as they rotate up to the work 5, when it is changed over to the work'- ing feed which continues until the cut is finished.

At the end of the cut the working feed is shut off by the control casing 8 and, by laying over the main lever ill to the left, the rotary motion of the spindles I is braked and brought to rest, whereupon the spindles return without rotating with the quick motion feed back to their initial position.

The axial displacement of the spindles I can also be effected by hand by means .of the hand wheel H. During this period the automatic feed is locked in the control casing 8. By means of the hand wheel l2 the slide 3 can be displaced to the left and the right. In the slide 3 and in the fixing plate 4 a longitudinal slot for the spindles I is provided. Fixed to the lower part 2 of the table is an indexing device for adjusting the axial distance between the bores, as required by the work 5. 4

The indexing device comprises a lower guiding ber proper I311. The guiding part l3 has straight dove-tail guides in which the indexing member l3a is slidably fitted, which is supported from below on an eccentric fixed on a spindle passing through a slot'in the indexing member and provided with an actuating handle 13, the indexing member bearing against the eccentric under the action of a powerful spring tending to force the indexing member into its lowermost position. By turning the handle I3 through degrees to the right from the position shown in Fig. 1, the indexing member is first of all lowered on the eccentric under the action of the spring into its lowermost position and during the further rotation of the handle the indexing member is immovably clamped to the guiding part l3, for

which purpose the spindle onwhich the handle I3 is fixed is provided with a screw thread which engages in a threaded hole provided in the back of the guiding part l3. When the handle I3 is turned to the left into the position shown in Fig. 1 the clamping action is first of all discontinued and the indexing member isthen raised by the eccentric against'theaction of the spring. The indexing member I3a bears at its upper end a hardened pointed locating member which fits one or more mating locating rests, which are slidably mounted on the slide 3 and can be bolted down on to the slide at any desired distances apart from one another.

On the spindle l is rigidly fixed the cutter head l4 with the cutter Hi. The chips produced in boring fall on the plate l6 which rotates with the spindle 'l and are thrown by centrifugal force against the wall of a tube I1 and conveyed through an opening ill in the wall into the chip box disposed in the bed.

The tube I1 is secured on to the main spindle bearing l9 and holdsa stationary sealing ring 20. By-this sealing ring 20 the plate IS with thenut 2| is secured against axial displacement. The annular channels turned in the plate It are filled with a sealing material 22 which carries round the plate I6 when the spindle 'l rotates and also wipes off the chips adhering to the spindle 1. Between the labyrinths of theplate l5 and the sealing ring 20 is a sealing material 23 which makes it impossible for chip particles which may penetrate through the gap 24 to enter the main bearing I9. I

For preventing the penetration of even the finest dust particles which might be carried along by the spindles I, there are provided below the plate l6 two further sealing rings 25 and 26 which take part in the rotary motion and which, lying one behind the other, prevent the penetration of even the finest chipparticles into the main hear-- ing l9 and its bush 21.

What I claim is:

1. In a machine for finish-boring cylinder blocks, a. box-like bed; a plurality of tool spindles vertically arranged and longitudinally spaced in the bed and adapted to be projected through an opening in the upper side of said bed, bearings for rotatably and axially guiding said spindles adjacent the upper surface of said bed, the upper portion of said bed being provided with horizontal guideways extending on opposite sides of said spindles longitudinally of said bed; a work table fitting said guideways for work positioning movement transversely of the spindles, provided with openings permitting projection of the spindles and adapted to hold the work in close proximity to said bearings; means for locking the table with 75 certain cylinder block bores in axial alignment with the spindles, and means within the bed for rotating and feeding the spindles.

. 2. In a machine for finish-boring cylinder blocks, a box-like bed; a plurality of tool spindles vertically arranged and longitudinally spaced in the bed, and adapted to be projected through an opening in the upper side of said bed, each of said spindles having a boring tool comprising a single cutting blade, bearings for rotatably and axially guiding said spindles adjacent the upper surface of said bed, the upper portion of said.

bed being provided with horizontal guideways extending on opposite sides of said spindles longitudinally of said bed; a work table fitting said guideways for work positioning movement transversely of the spindles, provided with openings permitting projection of the spindles and adapted to hold the work in close proximity to said bearings; means for locking the table with certain cylinder block bores'in axial alignment with the spindles, and means within the bed for rotating 10 and feeding the spindles.

' CUBT PLEGER. 

